Sheet feeding apparatus having an expansible periphery

Abstract

An apparatus having a track for guiding a sheet therealong and means for feeding a sheet along the track. The feeding means includes a rotatable member having a shaft mounted for rotation, with the rotatable member having a driving periphery extending into the track. The feeding means also includes a coupling unit and means for rotatably mounting the coupling unit at the track, with the coupling unit having an expansible periphery. Also provided is a means including an endless coiled spring for selectively moving the expansible periphery between a first position in which the expansible periphery is uncoupled from the driving periphery and a second position in which the expansible periphery is expanded to form a driving coupling with the driving periphery of the rotatable member to feed a sheet positioned therebetween along the track when the rotatable member is rotated.

I claim: 
     
       1. An apparatus comprising: a track for guiding a sheet therealong and;   means for feeding a sheet along said track;   said feeding means comprising:   a rotatable member having a shaft mounted for rotation; said rotatable member having a driving periphery extending into said track;   a coupling unit;   means for rotatably mounting said coupling unit at said track;   said coupling unit having an expansible periphery; and   means for selectively moving said expansible periphery between a first position in which said expansible periphery is uncoupled from said driving periphery and a second position in which said expansible periphery is expanded to form a driving coupling with said driving periphery of said rotatable member to feed a sheet positioned therebetween along said track when said rotatable member is rotated.   
     
     
       2. The apparatus as claimed in claim 1 in which said coupling unit includes a cylindrical member having a periphery and also having a resilient member mounted on the periphery of said cylindrical member to form said expansible periphery. 
     
     
       3. The apparatus as claimed in claim 1 in which said coupling unit includes an upper member and a lower member forming a peripheral wall with a space therebetween and also includes a first resilient member positioned on said coupling unit to expand into said space; said coupling unit having a second resilient member positioned on said peripheral wall forming said expansible periphery; and   said moving means including a member to expand said first resilient member into said space, causing said second resilient member to expand and to move into said second position to form said driving coupling when said moving means is moved in a first direction.   
     
     
       4. An apparatus comprising: a track for guiding a sheet therealong and;   means for feeding a sheet along said track;   said feeding means comprising:   a rotatable member having a shaft mounted for rotation; said rotatable member having a driving periphery extending into said track;   a coupling unit;   means for rotatably mounting said coupling units at said track;   said coupling unit having an expansible periphery; and   means for selectively moving said expansible periphery between a first position in which said expansible periphery is uncoupled from said driving periphery and a second position in which said expansible periphery is expanded to form a driving coupling with said driving periphery of said rotatable member to feed a sheet positioned therebetween along said track when said rotatable member is rotated;   said coupling unit including a cylindrical member having a periphery and also having a resilient member mounted on the periphery of said cylindrical member to form said expansible periphery;   said coupling unit including an upper member and a lower member forming a peripheral wall with a space therebetween and also including a first resilient member positioned on said coupling unit to expand into said space;   said coupling unit having a second resilient member positioned on said peripheral wall forming said expansible periphery; and   said moving means including a member to expand said first resilient member into said space, causing said second resilient member to expand and to move into said second position to form said driving coupling when said moving means is moved in a first direction;   said resilient member being a spring formed into a circle having a diameter and said member of said moving means being wedge-shaped to expand said diameter of said spring formed into said circle when said moving means is moved in said first direction.   
     
     
       5. The apparatus as claimed in claim 4 in which said spring is an endless coiled metal spring which is biased to form a contracting diameter to bias said wedge-shaped member of said moving means in a second direction which is opposite to said first direction. 
     
     
       6. The apparatus as claimed in claim 5 in which said second resilient member is in the form of an endless rubber band which is positioned on said peripheral wall. 
     
     
       7. The apparatus as claimed in claim 4 in which said mounting means comprises: a mounting plate having said track upstanding therefrom;   a rigid "C"-shaped support member secured to said mounting plate; and   shaft means for rotatably supporting and positioning said coupling unit in said rigid "C"-shaped support member to enable said expansible periphery to form said driving coupling;   said moving means including an actuator and coupling means to enable said actuator to move said wedge-shaped member in said first direction to expand said diameter of said spring when said actuator is energized.   
     
     
       8. The apparatus as claimed in claim 7 in which said lower member has an annular face on which said spring is positioned. 
     
     
       9. The apparatus as claimed in claim 8 in which said coupling means includes means to enable said coupling unit to rotate when said wedge-shaped member is moved in said first direction, and in which said wedge-shaped member is generally conically shaped. 
     
     
       10. The apparatus as claimed in claim 7 further comprising a cylindrically-shaped platen fixed to said shaft means for rotation therewith and a printer positioned at said track in operative relation with said cylindrically-shaped platen for printing on a said sheet positioned therebetween. 
     
     
       11. The apparatus as claimed in claim 10 in which said printer is a wire matrix printer having wire plungers which impact against said cylindrically-shaped platen when actuated. 
     
     
       12. An apparatus comprising: a track for guiding a sheet therealong;   first means including at least one first drive roller having a driving periphery for feeding a sheet along said track at a first rate of speed;   second means located downstream along said track with reference to said first means and also including a second drive roller for feeding a sheet along said track at a second rate of speed which is different from said first rate of speed;   said second drive roller having a driving periphery extending into said track;   said second means further comprising:   a coupling unit;   means for rotatably mounting said coupling unit at said track;   said coupling unit having an expansible periphery; and   means for selectively moving said expansible periphery between a first position in which said expansible periphery is uncoupled from said driving periphery of said second drive roller and a second position in which said expansible periphery is expanded to form a driving coupling with said driving periphery of said second drive roller to feed a sheet positioned therebetween along said track when said second drive roller is rotated;   said driving periphery of said second drive roller having a coefficient of friction which is greater than the coefficient of friction of the driving periphery of said first drive roller to enable said second means to control the feeding rate of a said sheet in said track when both said first means and second means are in feeding relationship with the same said sheet.   
     
     
       13. The apparatus as claimed in claim 12 in which said coupling unit includes a cylindrical member having a periphery and also having a resilient member mounted on the periphery of said cylindrical member to form said expansible periphery. 
     
     
       14. The apparatus as claimed in claim 12 in which said coupling unit includes an upper member and a lower member forming a peripheral wall with a space therebetween and also includes a resilient member positioned to expand into said space; said coupling unit having a second resilient member positioned on said peripheral wall forming said expansible periphery; and   said moving means including a member to expand said first resilient member into said space, causing said second resilient member to expand and to move into said second position to form said driving coupling when said moving means is moved in a first direction.   
     
     
       15. The apparatus as claimed in claim 14 in which said second means has a printer associated therewith and in which said second rate of speed is slower than said first rate of speed to enable said printer to be in printing relationship with a said sheet being fed by said second means; and in which said resilient member is a spring formed into a circle having a diameter and said member of said moving means is wedge-shaped to expand said diameter of said spring formed into said circle when said moving means is moved in said first direction.